Automatic brake mechanism.



No. 774,448. PATENTED NOV. 8, 1904.

A. E. NORRIS. AUTOMATIC BRAKE MECHANISM.

APPLICATION FILED NOV. 14, 1901.

N0 MODEL. 2 SHEETS-SHEET 1.

A. E. NORRIS.

PATENTED NOV. 8, 1904.

AUTOMATIC BRAKE MECHANISM.

APPLICATION FILED NOV. 14, 1901. N0 MODEL. Z SHEETS-EHEET 2.

Q Q q H L I I UNITED STATES Iatnted November Q, 1904.

PATENT EEicE.

AUTOMATIC BRAKE MECHANISM.

SPECIFICATION forming part of Letters Patent No. 774,448, dated November8, 1904. Application filed November 14, 1901. Serial No. 82,240. (Nomodel.)

To all whom it may concern,-

Be it known that I, ALMON E. NORRIS, a citizen of the United States,residing at Cambridge, in the county of Middlesex and State ofMassachusetts, have invented an Improvement in Automatic BrakeMechanism, of which the following description, in connection with theaccompanying drawings, is a specification, like numerals on the drawingsrepresenting like parts.

This invention relates to automatic brake mechanism, and is designedespecially as an improvement upon the automatic brake shown anddescribed in my reissued Patent N 0. 12,040, dated September 30, 1902.The said patented brake mechanism is especially adapted for use withhoisting devices and includes a brake-disk upon the shaft of a hoistingde-' vice and a brake-band surrounding said disk and having its endsconnected to an oscillatory actuator at different eifective distancesfrom an axis of oscillation. The patented device also showsautomatically-operative means for maintaining a frictional engagementbetween the brake-band and the brake-disk, whereby when the disk isrotated in one direction said frictional engagement causes thebrake-band and the actuator to move in one direction to relieve thebraking eifect, while when the brake-disk is rotated in the reverse oropposite direction said frictional engagement similarly acts to move thebrake-band and actuator in an opposite direction to increase the brakingeffect.

My present invention is an improvement over the devices above describedand which are illustrated in said patent, the said improvements relatingto the brake-band, the.brake-. disk, and the actuator. The brake-band isconstructed in such a way as to greatly increase the friction-surfacebetween the same and the friction-disk, and the actuator is soconstructed that it may be positively held in its inoperative position,thus providing means whereby the disk may be rotated backwardly, ifdesired. The brake-disk is also constructed in such a way as to providemeans for keeping the same cool. In order to accomplish these objects,the brake-band is what I have termed a bifurcated band and is of alength sufiicient to wrap twice around the periphery of the brake-disk.Approximately one-half of the brake-band is a single member, the band atsubstantially its central portion being forked to constitute two arms ormembers. In practice the brake-band is encircled about the brake-disktwice, and the ends of the said brake-band are fastened to the actuatorin some suitable way, the single member of the brake-band when the saidband is passed around the disk lying between the two branches or membersthereof, whereby the brake-disk has, in effect, three strands completelyencircling the same. This construction affords a greatly-increasedfriction-surface.

I have also provided suitable means, shown as an electromagnet, forpositively holding the actuator in an inoperative position with thebrake-band loose upon the brake-disk, whereby the disk may be rotatedbackwardly.

To keep the disk from being overheated by the friction between the bandand the brakesurface of the disk, I have shown the said disk as providedwith means for establishing currents of air through the same, whichcurrents operate to maintain the disk cool by convection.

In the drawings, Figure 1 is an end elevation of my improved brakemechanism. Fig. 2 is a side View thereof. Fig. 3 is a plan View of thebrake-band shown fiat. Fig. at is a side View of Fig. 8. Fig. 5 is asection on the line 00 02, Fig. 2. Fig. 6 is a section on the line 3/Fig. 2; and Fig. 7 is a similar view showing a modified form ofbrake-disk.

I have not in the drawings illustrated any particular kind of apparatusto which the brake mechanism is to be applied, as it is evident that thesaid brake is capable of being applied to any rotating shaft, therotation ofwhich in one direction it is desired to control by means ofthe brake. One illustration of the application of a similar brake is inthe case of hoisting apparatus, such as shown in my copend- 9 ingapplicatiomSerial N 034,532, filed October 27, 1900; but it will beobvious that the invention is not limited to use in connection withhoisting apparatus of this type.

3 in the drawings designates the shaft the rotation of which in onedirection it is desired to control by the brake, and if the brake isused in connection with a hoisting apparatus said shaft would be themain shaft on which the hoisting-drums were mounted. As illustrated saidshaft 8 is supported in any suitable bearing 4 and has fast thereon abrake-disk 5, about which is encircled the brake-band, as usual in thisclass of devices. The ends of the brake-band are fastened to anoscillatory actuator 6, which is supported to rock about a fixed pivot7, mounted in any suitable stationary support, and the ends of the brakeband are secured to the actuator at different distances from its axis ofrotation, as in my patent above referred to, the end 9 of the brakebandbeing shown connected with the actuator nearer its axis of rotation thanthe end 10 of said band. Automatically-operative means, such a spring31, operates to maintain the brakeband in frictional contact with thebrake-disk, as in my above-mentioned patent. With this construction andassuming that the shaft and brake-disk are rotating in the direction ofthe arrow (0 it will be understood that the friction between thebrake-band and brakedisk induced by the operation of spring 31 willcause the brake-band and the actuator to move into dotted-line position,Fig. 2. This movement of the actuator while slackening the end 10 of thebrake-band will tighten the end 9, and as the point of attachmentbetween the end 10 of the brake-band and the actuator is a greaterdistance from the axis of oscillation than the point of attachmentbetween the brake-band end 9 and said actuator there will be adifferential movement between the ends 9 and 10 in favor of the end 10suflicient to relieve the braking effect. \Vhen, however, the shaftrotates in the opposite direction, the said frictional engagementbetween the brakedisk and actuator will cause the actuator to move intothe full-line position, Fig. 2,whereby the braking effect will beincreased. For a more complete description of the operation of theseparts reference is made to the abovementioned patent.

To increase the effectiveness of the brakeband, I prefer to constructthe same as shown in Figs. 3 and 4:, the said brake-band being of atotal length sufficient to wrap twice about the brake-surface. Thepreferred brake-band comprises at one end@'. a, the end shown as 10 inFig. 2a single member 13, the said member extending approximately halfthe length of the band or being of a length suflicient to wrap onceabout the periphery of the brakedisk. The end of the member 13 isconnected to two branches 14:, each of which is of a length to wrap oncearound the brake-disk, the ends of the members 14 constituting the endof the brake-band shown as 9 in Fig. 2. The brakeband comprising thesingle member 13 for approximately half its length and the double memberfor the remainder of its length is what I term a bifurcated brake-bandfrom its peculiar shape.

In applying the brake-band to the brakedisk and assuming that the end 10thereof is connected to the actuator, as shown, the portion 13 of thebrake-band will be wrapped once around the periphery of the brake-diskin the usual manner, and thereafter the bifurcated portion constitutingthe branches 14: will be wrapped around the brake-disk. the saidbranches 14c lying upon the surface of the disk either side of thecentral single member 13, the structure of the bifurcated portion beingsuch as to admit of the member 13 being received between the branches M,as shown in Fig. 1. The ends 9 of the branches 14 will be connected tothe actuator, as shown in Fig. 2. Preferably the metallic band (shown inFig. 3) will have on its inner periphery the usual friction-blocks(shown by 20,) which blocks engage the periphery of the brake-disk, asin my former patent, and to prevent the brake-band from slippingtransversely of the disk I may attach to either the branches 14 or tothe central member 13 thereof the U-shaped guides 21, the ends of whichare bent down to engage the sides of the disk 5. By thus employing abifurcated brake-band I greatly increase the friction-sur face betweenthe brake-disk and brake-band, and by employing a construction in whichthe brake-band is wrapped a plurality of times about the brake-disk theeffectiveness of the brake is greatly increased, for with the sameamount of tension applied to the brake-band the band is made to grip thedisk more firml y.

To still further increase the efiectiveness of the brake I may make theblocks 20 V-shaped in crosssection, as shown in Fig. 6, the pointedportion of the said blocks engaging corresponding grooves in theperiphery of the disk. This construction affords means for still furtherincreasing the amount of friction surface between the brake-disk andbrake-band. I may, however, if desired, employ the ordinary constructionof block 20, such' as shown in Fig. 7

The particular form of actuator which I employ is similar to that shownin my former patent@'. 0., it comprises the two side members 26 and 26,through which pass the rods 27 and 28, to which eyes in the ends 9 and10, respectively, of the brakeband are connected.

The ends of the two members 1 1 of the brake-band may be spaced by anysuitable means, such as collars 29 upon the rod 27, and I preferablyemploy on the rod 28 collars or other suitable devices 30 for centeringthe eye of the single member 14 of the band.

Since the operation of the brake is dependent entirely upon the factthat a constant frictional engagement between the brakeband andbrake-disk is maintained, it is necessary to provide some means forpreventing the actuator 'from becoming turned to such an extent astodestroy such frictional engagement, and in this embodiment of myinvention I have provided means independent from the actuator andbrake-band for thus limiting the movement of the actuator in a directionto relieve the braking effect. It is sometimes desirable to be able torotate the shaft supporting the brake-disk in a backward or reversedirection without setting the brake, and I have therefore provided meanswhereby the actuator may be positively held in the dotted-line position.Fig. 2, so as to maintain the brake-band in such position that thefrictional engagement between the latter and the brake'disk will be at aminimum regardless of the direction of rotation of said brakedisk. Themeans which I preferably employ to accomplish the latter result is oneor more electromagnets 40, suitably mounted upon the standard at, whichmagnets cooperate with a bar 41, connected to the actuator 6, which baris, in effect, an armature for the magnets. hen now the magnets areenergized through any suitable means, the armature 41 is attracted andthe actuator 6 oscillated into dot ted-line position, Fig. 2, therebyloosening the brake-band, and by properly proportioning the strength ofthe magnets 40 the brakeband may be held in its ineffective orloosenedcondition while the disks and shaft are rotated backwardly to anydesired extent. By simply deenergizing the magnet the brake will againbecome automatic to stop further backward rotation of the shaft, asexplained above. The magnets and armature also have the function of astop device, which is independent from the actuator to limit themovement of the actuator in a direction to loosen the brake' band, forit will be obvious that when the disk rotates in the direction of thearrow (6 the friction between the band and brake-disk will bring theactuator into dotted-line position, thus bringing the armature againstthe magnets, the said magnets preventing the further oscillatorymovement of the actuator.

The constant frictional engagement between the brake-disk and thebrake-band, which is necessary for the proper operation of this device,is liable to generate suflicient heat to impair the perfect operation ofthe brake and to prevent the parts from becoming overheated. I haveprovided means whereby the rotation of the disk will establish currentsof air through the same, whereby the heat which is generated will becarried away by convection. For this purpose the brake-disk hasextending therethrough near its periphery a series of inclinedpassage-ways or air-vents 50, said airvents being formed by the rim 51of the wheel and the inclined partitions or ribs 52. It will be obviousin view of this construction that whenever the disk is rotated the ribs52 operate something as a fan and serve to establish currents of airthrough the passage-ways 50,

thereby preventing the rim of'the brake-disk from becoming overheated.

While I have shown one embodiment of my invention, it is obvious thatthe structure illustrated may be changed in matter of detail in manyways without altering the invention as expressed in the appended claims,some of which are quite broad.

Having described my invention, what I claim, and desire to secure byLetters Patent, 1st 1. A brake mechanism comprising a brakedisk, abrake-band surrounding said disk, an oscillatory actuator to which theends of the brake-band are connected at different elfective distancesfrom the axis of oscillation, automatically-operative means acting tomaintain a frictional engagement between the brake-band and the disk,whereby rotation of the brakedisk in onedirection acts through saidfrictional engagement upon and to move said brake-band and actuator in adirection to relieve the braking efi'ect, and rotation of the disk in areverse direction similarly acts to move said brake-band and actuator ina direction to increase the braking effect, and means independent fromthe actuator to limit the movement of the latter in the first-nameddirection.

2. A brake mechanism comprising a brakedisk, a brake-band surroundingsaid disk, an oscillatory actuator to which the ends of the brake-bandare connected at different efi'ective distances from the axis ofoscillation, automatically-operative means acting to maintain africtional engagement between the brake band and disk, whereby rotationof the brake-disk in one direction acts through said frictionalengagement upon and to move said brakeband and actuator in a directionto relieve the braking effect and rotation ofthe disk in a reversedirection similarly acts to move said brake-band and actuator in adirection to increase the braking effect ,and means whereby the actuatormay be held positively from movement in the last-named direction.

8. In a brake mechanism, a brake-disk, a brake-band encircling saiddisk, means acting through frictional engagement of the disk and brakeband to increase automatically the braking effect upon a reverse orbackward rotation of said disk, and means to hold positively thebrake-band in its ineffective position.

4. In a brake mechanism, a brake-disk, a i

brake-band encircling said brake-disk, electromagnetic devices operatingwhen energized to hold said brake-band inactive, and means renderedoperative when the electromagnetic devices are inactive and by thefrictional engagement between the brake band and disk on the backward orreverse rotation of the latter to increase automatically the brakingeffect. I

5; In a brake mechanism, a brake-disk, a

IIO

brake-band cooperating therewith, means acting through frictionalengagement between brake band and disk to increase the braking effectwhen the brake-disk rotates in one direction and to relieve the brakingeffect when the said disk rotates in the opposite direction, and meansindependent from the brake-band to limit the extent to which the brakingefiect is relieved.

6. In a brake mechanism, a brake-disk, a brake-band cooperatingtherewith, an oscillatory actuator to which the ends of the brakebandare connected at different effective distances from the axis ofoscillation, automatically operative means to maintain a frictionalengagement between the brake disk and brake-band, whereby rotation ofthe brakedisk in one direction acts through said frictional engagementto move the brake-band and actuator in a direction to relieve thebraking etfect and rotation of the disk in a reverse direction similarlyacts to increase the braking effect, combined with a magnet, thearmature of which is rigid with the actuator, the construction beingsuch that when the magnet is energized the actuator is held in itsinefiective position, said magnet also operating as a stop to limit themovement of the actuator in the direction to relieve the braking effect.

7 In a brake mechanism, a brake-disk, a brake-band cooperating with saiddisk, said brake-band being of a length to wrap around the brake-disk aplurality of times, means to hold positively said brake-band in itsineifective position, and means rendered operative by the frictionalengagement between the brakeband and brake-disk when the latter is r0-tated backwardly to increase the braking effeet.

8. In a brake mechanism, a brake-disk, a brake-band cooperatingtherewith,saiol brakeband being of a length to wrap twice about thebrake-disk andpresenting a single member for approximately half itslength and two parallel members spaced from each other for the remainderof its length, and means rendered operative by the frictional engagementbetween the brake-band and the brake-disk to increase the braking eifectwhen the latter rotates backwardly.

In testimony whereofI have signed my name to this specification in thepresence of two subscribing witnesses.

ALMON E. NORRIS.

Witnesses:

LoUIs C. SMITH, Gno. H. MAXWELL.

